Early cellular telephones included large housings which contained large and heavy batteries and extensive electronic circuitry. As cellular telephones developed over the years, their size has steadily decreased. This has been partly due to the integration of electronic functions into semiconductor devices such as digital signal processors specifically designed to process the electrical operations of a cellular telephone. In addition, smaller, more powerful batteries have been developed.
Though cellular telephones have become smaller and smaller, the typical cellular telephone is still larger than a user's pocket. This requires a user to either carry the cellular telephone in a bag or briefcase, or carry the cellular telephone in his hand. However, these methods of carrying a cellular telephone are not as convenient as carrying the cellular telephone in the user's pocket. Thus, cellular telephone manufacturers have attempted to make cellular telephones which will fit into a user's pocket.
One limiting factor in making cellular telephones smaller is the form and function requirements relating to operation of the telephone. One of these requirements is that the user must be able to speak into a microphone and simultaneously listen to sounds from a speaker.
Another limiting factor in making cellular telephones smaller is the telephone display. A cellular telephone must generally have a display of a sufficient size so as to allow a user to easily see displayed data. The display must be located such that a user may readily see the display. Thus, displays are typically located on the front surface of the telephone.
Most cellular telephones include function keys. These flnction keys are typically used to initiate calls and to end calls. Some designs also include function keys which are used for other various purposes. These function keys must be conveniently located since they are frequently used. Thus, function keys are typically located on the front surface of the telephone.
Prior art cellular telephones typically include a keypad which is located on the front surface of the telephone. The keypad is used to enter in the number to be dialed. The keypad also limits the size of the telephone since the keypad must be of a sufficient size so as to allow a user to easily enter numbers by manually operating the keys of the keypad. A keypad which is of a sufficient size so as to allow for easy operation (a full size keypad) is relatively large. Since keypads are typically placed on the front of the telephone, much of the front surface of the telephone is taken up by the keypad. This leaves little room for the speaker, the display and any function keys.
Some prior art telephone designs allow a user to input names and phone numbers of frequently called numbers. The user may then scroll through the names and phone numbers either using the keypad or using one or more dedicated function keys. However, since most of the front surface of the telephone is taken up by the keypad and function keys, there is little room left for a display. Thus, most prior art telephones have very small displays. Typically, these prior art displays only have room enough for a one-line display as a user scrolls through the numbers. This makes the function of scrolling through stored names and numbers a difficult and time consuming process. For this reason, many users do not use the stored frequently called numbers to make a call. Instead, they simply remember the frequently called numbers or look them up prior to manually dialing the number using the keys of the keypad.
What is needed is a cellular telephone which is small enough to fit into a user's pocket and which includes an adequately sized display and an adequately sized keypad. In addition, a telephone which is easy to use and which is designed such that a user may easily use stored names and numbers to make calls. The present invention meets the above needs.